Complete syndactyly
A condition in which singers or toes are completely joined together, with the connection extending from the base to the tip of the involved digits.
Complete syndactyly is the opposite of partial syndactyly, in which the connection extends only part of the way up from the base of the involved digits.
The word 'syndactyly' is compounded from the Greek roots 'syn-' (together) + 'dactylos' (finger) = fingers together.